A seven-month-old girl died while six other children are undergoing treatment at a government hospital after being administered anti-polio vaccine in Bihar's Vaishali district, Doctors said today.

Civil Surgeon (CS) of Vaishali Ramashish Kumar said that Sonali Kumari, a seven-month-old girl, died at her home late last night after she was administered the anti-polio injection during the day at Shahpur village.

The Centre termed as "sudden infant death syndrome" the fatality and sought a report from the state government.

Six other children of the village under Ganga bridge police station have been admitted to Sadar hospital for treatment, Kumar said.

Sadar Hospital doctor B N Jha, who is treating the children at the hospital, said they reported complaints of vomiting and shivering among other problems.

The CS said a team under Executive Director of state Health department Rahul Kumar has gone to the village to probe the matter.

He said that till now anti-polio drops used to be given to children and this was the first time that the vaccination centre of the district went for administering anti-polio injections.

"It seems to be a case of sudden infant death syndrome. Post mortem is being conducted," a senior Union Health Ministry official said in Delhi.

According to the investigation by the Ministry's team, the child was unwell before being given the vaccine.

"All children were fine except for the one who was found dead in the morning. She already had mild fever and parents also do not know the reason," the official said.

He said that the six other children who reportedly fell sick were brought to the hospital as a "panic reaction".

"As a panic reaction, all the children who were vaccinated in that locality were brought to the hospital and were finally discharged after two hours of observation," the official said.